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双柱液压式汽车举升机设计【全套6张CAD图纸和毕业论文】【汽车专业】

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摘要

双柱式举升机是一种汽车修理和保养单位常用的举升设备,广泛用于轿车等小型车的维修和保养。它是一种把整车装备重量不大于3吨的各种轿车、面包车、工具车等举升到一定高度内供汽车维修和安全检查作业的保修设备。
关键词  升举机  液压执行元件  起重链  槽轮   钢丝绳  


Abstract
A pillar type raises to rise the machine is a kind of automobile to fix and maintain the unit to raise to rise the equipments in common usely, extensively used for the car etc. the compact car maintains and maintains.It is a kind of is no bigger than 3 tons the whole car  material weight of various car, bread car, the tool car...etc. raise to rise the certain height to be provided for car maintenance and safeties to check the homework protect to fix the equipments.

keyword   UP hydraulic power WRAPT    hydraulic pressure action element    hoisting chain     grooved pulley   wire rope


目 录
摘要 I
Abstract II
第1章  绪论 6
1前言 6
2升举机的概述 7
第2章  总体设计 8
第3章 主要技术特点及其技术参数 9
1 技术特点 9
2技术参数 9
第4章 液压系统的传动计算 10
1  液压系统的设计步骤与设计要求 10
2  进行工况分析、确定液压系统的主要参数 11
3 制定基本方案和绘制液压系统图 20
4  液压元件的选择与专用件设计 22
5 液压系统性能验算 27
第5章  液压执行元件 34
1 液压缸 34
2 液压马达 45
第6章  液压辅助元件及液压泵站 46
1 管件 46
2. 液压软管接头 46
3 油箱及其附件 47
4  UP液压动力包 47
6.液压油的选择 51
第7章  钢丝绳的选择计算 52
1 钢丝绳的计算 52
2 钢丝绳的选择 52
第8章  滑轮的选择和计算 54
1 滑轮结构和材料 54
2 滑轮的主要尺寸 54
3 滑轮直径与钢丝绳直径匹配关系 54
4 滑轮形式 54
5 滑轮技术条件 54
6 滑轮强度计算 55
第9章 起重链条和槽轮 56
1 板式链条和槽轮的选择 56
2 板式链及端接头 56
3 板式链用槽轮 56
第10章  使用说明 57
1.使用说明 57
2使用时注意事项 57
3.升举机安全操作规程 57
第11章 经济效益分析 58
总  结 59
谢  辞 60
参考文献 61
专题 62
附录 68



内容简介:
黑龙江科技学院毕业设计(论文)任务书姓名:吴建芳 任务下达日期: 2006 年 3 月 13 日设计(论文)开始日期: 2006 年 3 月 13 日设计(论文)完成日期: 2006 年 6 月 20 日一、设计(论文)题目:小汽车维修用液压升举装置 二、专题题目: 高速切削技术及其应用 三、设计的目的和意义:随着中国经济的蓬勃发展,小客车将逐步进入中国的家庭市场。鉴于中国市场的广阔性,及其中国基础设施的滞后性,给小客车的维修带来了不便,特别是轿车底部的维修,给维修师傅带来很多不便,浪费人力物力,还有占地面积,为了解决上属的所有问题,为未来社会的发展带来方便。小客车维修用升举装置主要应用于家庭和出租车类。应用十分的广泛,主要用途是通过升举实现维修的方便和安全。四、设计(论文)主要内容:小汽车维修用液压升举机总装配图(1张0号)、托举装置装配图(1张0号)、液压缸装配图(1张1号)、液压原理图(1张3号)、活塞零件图(1张2号)、液压缸后端盖零件图(一张2号). 五、设计目标:实现液压传动装置的平稳升举六、进度计划: 2006年3月13日至3月31日进行为期3周的生产实习;4月1日至4月15日完成对设计题目的资料收集与查询;4月16日至5月13日完成对设计图纸的绘制;5月14日至6月10日完成毕业设计说明书的编写;6月11日至6月20日最后的审稿及说明书和图纸的打印。 七、参考文献资料: 1 许福玲、陈尧明主编 液压与气压传动 机械工业出版社 2000 2 王宪军、赵存友主编 液压传动M 哈尔滨工业大学出版社20023庞振基、黄其圣主编 精密机械设计M 机械工业出版社 20004刘鸿文主编材料力学(第二版)M 高等教育出版社 19925黄靖远、龚剑霞主编 机械设计学M 机械工业出版社 20026袁绩乾、李文贵主编 机械制造技术基础M 机械工业出版社20017朱龙根主编 机械系统技术(第二版)M 机械工业出版社20018冯辛安主编 机械制造装备设计M 机械工业出版社 20029曹德芳主编 汽车维修M 人民交通出版社,1999. 70- 78.10王静文主编 汽车诊断与检测技术M 人民交通出版社 1998. 90- 120 11邵松明主编 汽车维护与修理M人民交通出版社 2003, (1): 1- 2。指 导 教 师: 院(系)主管领导: 年 月 日2I摘要摘要双柱式举升机是一种汽车修理和保养单位常用的举升设备,广泛用于轿车等小型车的维修和保养。它是一种把整车装备重量不大于 3 吨的各种轿车、面包车、工具车等举升到一定高度内供汽车维修和安全检查作业的保修设备。关键词关键词 升举机 液压执行元件 起重链 槽轮 钢丝绳 IIAbstractA pillar type raises to rise the machine is a kind of automobile to fix and maintain the unit to raise to rise the equipments in common usely, extensively used for the car etc. the compact car maintains and maintains.It is a kind of is no bigger than 3 tons the whole car material weight of various car, bread car, the tool car.etc. raise to rise the certain height to be provided for car maintenance and safeties to check the homework protect to fix the equipments.keyword UP hydraulic power WRAPT hydraulic pressure action element hoisting chain grooved pulley wire rope1目 录摘要.IABSTRACT.II第 1 章 绪论.61 前言.62 升举机的概述.7第 2 章 总体设计.8第 3 章 主要技术特点及其技术参数.91 技术特点 .92 技术参数.9第 4 章 液压系统的传动计算.101 液压系统的设计步骤与设计要求.102 进行工况分析、确定液压系统的主要参数.113 制定基本方案和绘制液压系统图 .204 液压元件的选择与专用件设计.225 液压系统性能验算 .27第 5 章 液压执行元件.341 液压缸 .342 液压马达 .452第 6 章 液压辅助元件及液压泵站.461 管件 .462. 液压软管接头 .463 油箱及其附件 .474 UP 液压动力包 .476液压油的选择 .51第 7 章 钢丝绳的选择计算.521 钢丝绳的计算 .522 钢丝绳的选择 .52第 8 章 滑轮的选择和计算.541 滑轮结构和材料 .542 滑轮的主要尺寸 .543 滑轮直径与钢丝绳直径匹配关系 .544 滑轮形式 .545 滑轮技术条件 .546 滑轮强度计算 .55第 9 章 起重链条和槽轮.561 板式链条和槽轮的选择 .562 板式链及端接头 .563 板式链用槽轮 .56第 10 章 使用说明.571使用说明.5732 使用时注意事项 .573.升举机安全操作规程 .57第 11 章 经济效益分析.58总 结.59谢 辞.60参考文献.61专题.62附录.68本科毕业论文(设计)开题报告论文题目专业名称年 级学生学号学生姓名指导教师(职称)填表时间 年 月 日教 务 处 制填 表 说 明一、开题报告各项内容要实事求是,逐条认真填写,表达要明确、严谨。外来语应用中文和英文同时表达,第一次出现的缩写词,须注出全称。二、开题报告需用计算机打印,一律为A4开本,于左侧装订成册。各栏空格不够时,请自行加页。三、开题报告需在第八学期开学之前完成。指导教师基本情况指导教师姓名性别年龄学历或学位专业技术职务或职称工 作 单 位课题来源1、导师课题的一部分; 2、其它(须具体说明): 。1、该研究的目的、意义现代汽车工业随着科学技术的飞速发展而日新月异, 新工艺、新材料、新技术广泛运用, 特别是电子技术、液压技术在汽车上应用, 使当今的汽车是集各种先进技术的大成, 新颖别致的汽车时时翻新。而现代汽车的故障诊断不再是眼看、耳听、手摸, 汽车维修也不再是师傅带徒弟的一门手艺, 而是利用各种新技术的过程。随着汽车技术的快速发展, 日益呈现出汽车维修的高科技特征, 与其同时汽车维修理念也不断更新。鉴于中国市场的广阔性,及其中国基础设施的滞后性,给汽车的维修带来了不便,特别是轿车底部的维修,给维修师傅带来很多不便,浪费人力物力,还有占地面积,为了解决上属的所有问题,为未来社会的发展带来方便。汽车维修用升举装置主要应用于家庭和出租车类。应用十分的广泛,主要用途是通过升举实现维修的方便和安全。2、国内外研究现状及发展趋势汽车维修行业规模不断扩大 ,结构不断优化 十年来 ,我国的维修行业整体规模有了较大的发展和提高。目前 ,我国已从根本上解决了 长期存在的“修车难”问题,取而代之的是一些不成形的小企业 ,由于维修设备不完善、人员技术能力差而无法在竞争的环境下生存。国内维修企业已从传统的单一车辆维修发展为车辆维修、车辆检验、配件 销售三位一体的综合体系。近年来 ,配件市场有了 较大的发展 ,配件销售规模越来越大。车辆检测也 从无到有 ,建成了汽车综合检测站 ,拥有了完整先进的检测设备。车辆维修也从过去只能修中型车、国产车、汽油车发展到能维修重型车、小型车、柴油车 和进口车。维修企业小而全、全能的经营方式已向 专业化分工方向发展。十年来 ,各类专业维修中心近 60 家 ,产业结构优化布局更趋合理 ,高档车维修可就地完成,维修网络系统完善 ,为汽车使用单位提 供了便利条件。目前国内汽车维修技术水平、管理能力、经营方式、生产规模、从业人员的综合素质和服务意识, 与发达国家相比还存在较大差距, 如在实现汽修业的配件送货及全方位的零库存等。我国汽车维修的经营方式将逐步与国际接轨, 多种经营方式已全面展开, 如特约维修、代理维修、现场维修、专项总成维修, 也将实 现连锁经营维修、定点维修、会员制方式维修及俱乐部方式的维修等。充分体现低成本, 以专一保证质量和服务的优越性。现在汽车维修,大多采用地沟作业,工作空间狭小,积油积水后排出困难,沟内阴暗,需人工采光,通风不良,工作起来极其不便。有了此类升举装置,将会给维修带来效率,还能减轻工人师傅的劳动强度。故此,小较车维修用升举机具有很大的市场前景。3、主要参考文献见说明书4、该研究的简要内容,重点解决的问题,预期结果或成果预期成果:小汽车维修用液压升举机总装配图(1张0号)、托举装置装配图(1张0号)、液压缸装配图(1张1号)、液压原理图(1张3号)、活塞零件图(1张2号)、液压缸后端盖零件图(一张2号).5、拟采取的研究方法或实验方法,步骤,可能出现的技术问题及解决办法经过调研了解到,国内市场对于维修用升举机的需求量比较大,考虑到国内的特点,从实用角度出发,确定如下方案:1. 考虑到大多数维修是屋内作业,野外作业有,但是少,故采用两立柱升举,尽量在满足升举条件的情况下,节省空间。2. 为了减少噪音及其达到升降的平稳性采用液压动力升举装置。3. 由于升举的同时,两个同步液压缸的设计不可能完全一样,将导致升举的同时车会发生倾斜,故采用钢丝绳平稳系统,以消除该影响。4. 在满足上述要求的同时,尽量结构简单,操作方便,适用于整体或解体搬运尽量做到标准化,通用化,系列化。6、完成该研究已具备的条件1.大量相关课题资料的收集与整理2.机械设计专业知识学习3.计算机辅助设计软件的熟练掌握指导教师意见签名:年 月 日教研室意见教研室负责人:时间: 年 月 日教学院系部意见教学院系部负责人:时间: 年 月 日附录 (外文翻译原文)Fundamentals of Mechanical Design Mechanical design means the design of things and systems of a mechanical naturemachines, products, structures, devices, and instruments. For the most part mechanical design utilizes mathematics, the materials sciences, and the engineering-mechanics sciences. The total design process is of interest to us. How does it begin? Does the engineer simply sit down at his desk with a blank sheet of paper? And, as he jots down some ideas, what happens next? What factors influence or control the decisions which have to be made? Finally, then, how does this design process end? Sometimes, but not always, design begins when an engineer recognizes a need and decides to do something about it. Recognition of the need and phrasing it in so many words often constitute a highly creative act because the need may be only a vague discontent, a feeling of uneasiness, of a sensing that something is not right. The need is usually not evident at all. For example, the need to do something about a food-packaging machine may be indicated by the noise level, by the variations in package weight, and by slight but perceptible variations in the quality of the packaging or wrap.There is a distinct difference between the statement of the need and the identification of the problem. which follows this statement. The problem is more specific. If the need is for cleaner air, the problem might be that of reducing the dust discharge from power-plant stacks, or reducing the quantity of irritants from automotive exhausts.Definition of the problem must include all the specifications for the thing that is to be designed. The specifications are the input and output quantities, the characteristics of the space the thing must occupy and all the limitations on these quantities. We can regard the thing to be designed as something in a black box. In this case we must specify the inputs and outputs of the box together with their characteristics and limitations. The specifications define the cost, the number to be manufactured, the expected life, the range, the operating temperature, and the reliability. There are many implied specifications which result either from the designers particular environment or from the nature of the problem itself. The manufacturing processes which are available, together with the facilities of a certain plant, constitute restrictions on a designers freedom, and hence are a part of the implied specifications. A small plant, for instance, may not own cold-working machinery. Knowing this, the designer selects other metal-processing methods which can be performed in the plant. The labor skills available and the competitive situation also constitute implied specifications. After the problem has been defined and a set of written and implied specifications has been obtained, the next step in design is the synthesis of an optimum solution. Now synthesis cannot take place without both analysis and optimization because the system under design must be analyzed to determine whether the performance complies with the specifications.The design is an iterative process in which we proceed through several steps, evaluate the results, and then return to an earlier phase of the procedure. Thus we may synthesize several components of a system, analyze and optimize them, and return to synthesis to see what effect this has on the remaining parts of the system. Both analysis and optimization require that we construct or devise abstract models of the system which will admit some form of mathematical analysis. We call these models mathematical models. In creating them it is our hope that we can find one which will simulate the real physical system very well. Evaluation is a significant phase of the total design process. Evaluation is the final proof of a successful design, which usually involves the testing of a prototype in the laboratory. Here we wish to discover if the design really satisfies the need or needs. Is it reliable? Will it compete successfully with similar products? Is it economical to manufacture and to use? Is it easily maintained and adjusted? Can a profit be made from its sale or use? Communicating the design to others is the final, vital step in the design process. Undoubtedly many great designs, inventions, and creative works have been lost to mankind simply because the originators were unable or unwilling to explain their accomplishments to others. Presentation is a selling job. The engineer, when presenting a new solution to administrative, management, or supervisory persons, is attempting to sell or to prove to them that this solution is a better one. Unless this can be done successfully, the time and effort spent on obtaining the solution have been largely wasted. Basically, there are only three means of communication available to us. There are the written, the oral, and the graphical forms. Therefore the successful engineer will be technically competent and versatile in all three forms of communication. A technically competent person who lacks ability in any one of these forms is severely handicapped. If ability in all three forms is lacking, no one will ever know how competent that person is!The competent engineer should not be afraid of the possibility of not succeeding in a presentation. In fact, occasional failure should be expected because failure or criticism seems to accompany every really creative idea. There is a great to be learned from a failure, and the greatest gains are obtained by those willing to risk defeat. In the find analysis, the real failure would lie in deciding not to make the presentation at all. Introduction to Machine Design Machine design is the application of science and technology to devise new or improved products for the purpose of satisfying human needs. It is a vast field of engineering technology which not only concerns itself with the original conception of the product in terms of its size, shape and construction details, but also considers the various factors involved in the manufacture, marketing and use of the product. People who perform the various functions of machine design are typically called designers, or design engineers. Machine design is basically a creative activity. However, in addition to being innovative, a design engineer must also have a solid background in the areas of mechanical drawing, kinematics, dynamics, materials engineering, strength of materials and manufacturing processes. As stated previously, the purpose of machine design is to produce a product which will serve a need for man. Inventions, discoveries and scientific knowledge by themselves do not necessarily benefit people; only if they are incorporated into a designed product will a benefit be derived. It should be recognized, therefore, that a human need must be identified before a particular product is designed. Machine design should be considered to be an opportunity to use innovative talents to envision a design of a product is to be manufactured. It is important to understand the fundamentals of engineering rather than memorize mere facts and equations. There are no facts or equations which alone can be used to provide all the correct decisions to produce a good design. On the other hand, any calculations made must be done with the utmost care and precision. For example, if a decimal point is misplaced, an otherwise acceptable design may not function. Good designs require trying new ideas and being willing to take a certain amount of risk, knowing that is the new idea does not work the existing method can be reinstated. Thus a designer must have patience, since there is no assurance of success for the time and effort expended. Creating a completely new design generally requires that many old and well-established methods be thrust aside. This is not easy since many people cling to familiar ideas, techniques and attitudes. A design engineer should constantly search for ways to improve an existing product and must decide what old, proven concepts should be used and what new, untried ideas should be incorporated. New designs generally have “bugs” or unforeseen problems which must be worked out before the superior characteristics of the new designs can be enjoyed. Thus there is a chance for a superior product, but only at higher risk. It should be emphasized that, if a design does not warrant radical new methods, such methods should not be applied merely for the sake of change. During the beginning stages of design, creativity should be allowed to flourish without a great number of constraints. Even though many impractical ideas may arise, it is usually easy to eliminate them in the early stages of design before firm details are required by manufacturing. In this way, innovative ideas are not inhibited. Quite often, more than one design is developed, up to the point where they can be compared against each other. It is entirely possible that the design which ultimately accepted will use ideas existing in one of the rejected designs that did not show as much overall promise. Psychologists frequently talk about trying to fit people to the machines they operate. It is essentially the responsibility of the design engineer to strive to fit machines to people. This is not an easy task, since there is really no average person for which certain operating dimensions and procedures are optimum.Another important point which should be recognized is that a design engineer must be able to communicate ideas to other people if they are to be incorporated. Initially the designer must communicate a preliminary design to get management approval. This is usually done by verbal discussions in conjunction with drawing layouts and written material. To communicate effectively, the following questions must be answered:(1) Does the design really serve a human need?(2) Will it be competitive with existing products of rival companies?(3) Is it economical to produce?(4) Can it be readily maintained?(5) Will it sell and make a profit? Only time will provide the true answers to the preceding questions, but the product should be designed, manufactured and marketed only with initial affirmative answers. The design engineer also must communicate the finalized design to manufacturing through the use of detail and assembly drawings. Quite often, a problem well occur during the manufacturing cycle. It may be that a change is required in the dimensioning or tolerancing of a part so that it can be more readily produced. This falls in the category of engineering changes which must be approved by the design engineer so that the product function will not be adversely affected. In other cases, a deficiency in the design may appear during assembly or testing just prior to shipping. These realities simply bear out the fact that design is a living process. There is always a better way to do it and the designer should constantly strive towards finding that better way. Machining Turning The engine lathe, one of the oldest metal removal machines, has a number of useful and highly desirable attributes. Today these lathes are used primarily in small shops where smaller quantities rather than large production runs are encountered.The engine lathe has been replaced in todays production shops by a wide variety of automatic lathes such as automatic of single-point tooling for maximum metal removal, and the use of form tools for finish and accuracy, are now at the designers fingertips with production speeds on a par with the fastest processing equipment on the scene today.Tolerances for the engine lathe depend primarily on the skill of the operator. The design engineer must be careful in using tolerances of an experimental part that has been produced on the engine lathe by a skilled operator. In redesigning an experimental part for production, economical tolerances should be used.Turret Lathes Production machining equipment must be evaluated now, more than ever before, in terms of ability to repeat accurately and rapidly. Applying this criterion for establishing the production qualification of a specific method, the turret lathe merits a high rating. In designing for low quantities such as 100 or 200 parts, it is most economical to use the turret lathe. In achieving the optimum tolerances possible on the turret lathe, the designer should strive for a minimum of operations. Automatic Screw Machines Generally, automatic screw machines fall into several categories; single-spindle automatics, multiple-spindle automatics and automatic chucking machines. Originally designed for rapid, automatic production of screws and similar threaded parts, the automatic screw machine has long since exceeded the confines of this narrow field, and today plays a vital role in the mass production of a variety of precision parts. Quantities play an important part in the economy of the parts machined on the automatic to set up on the turret lathe than on the automatic screw machine. Quantities less than 1000 parts may be more economical to set up on the turret lathe than on the automatic screw machine. The cost of the parts machined can be reduced if the minimum economical lot size is calculated and the proper machine is selected for these quantities.Automatic Tracer Lathes Since surface roughness depends greatly upon material turned, tooling ,and fees and speeds employed, minimum tolerances that can be held on automatic tracer lathes are not necessarily the most economical tolerances.Is some case, tolerances of 0.05mm are held in continuous production using but one cut. Groove width can be held to 0.125mm on some parts. Bores and single-point finishes can be held to 0.0125mm. On high-production runs where maximum output is desirable, a minimum tolerance of 0.125mm is economical on both diameter and length of turn.Milling With the exceptions of turning and drilling, milling is undoubtedly the most widely used method of removing metal. Well suited and readily adapted to the economical production of any quantity of parts, the almost unlimited versatility of the milling process merits the attention and consideration of designers seriously concerned with the manufacture of their product. As in any other process, parts that have to be milled should be designed with economical tolerances that can be achieved in production milling. If the part is designed with tolerances finer than necessary, additional operations will have to be added to achieve these tolerancesand this will increase the cost of the part. Grinding Grinding is one of the most widely used methods of finishing parts to extremely close tolerances and low surface roughness. Currently, there are grinders for almost for almost every type of grinding operation. Particular design features of a part dictate to a large degree the type of grinding machine required. Where processing costs are excessive, parts redesigned to utilize a less expensive, higher output grinding method may be well worthwhile. For example, wherever possible the production economy of centerless grinding should be taken advantage of by proper design consideration. Although grinding is usually considered a finishing operation, it is often employed as a complete machining process on work which can be ground down from rough condition without being turned or otherwise machined. Thus many types of forgings and other parts are finished completely with the grinding wheel at appreciable savings of time and expense. Classes of grinding machines include the following: cylindrical grinders, centerless grinders, internal grinders, surface grinders, and tool and cutter grinders.The cylindrical and centerless grinders are for straight cylindrical or taper work; thus splines, shafts, and similar parts are ground on cylindrical machines either of the common-center type or the centerless machine.Thread grinders are used for grinding precision threads for thread gages, and threads on precision parts where the concentricity between the diameter of the shaft and the pitch diameter of the thread must be held to close tolerances.The internal grinders are used for grinding of precision holes, cylinder bores, and similar operations where bores of all kinds are to be finished.The surface grinders are for finishing all kinds of flat work, or work with plain surfaces which may be operated upon either by the edge of a wheel or by the face of a grinding wheel. These machines may have reciprocating or rotating tables.(外文翻译汉文)机械设计基础机械设计基础是指机械装置和机械系统机器、产品、结构、设备和仪器的设计。大部分机械设计需要利用数学、材料科学和工程力学知识。 我们对整个设计过程感兴趣。它是怎样开始的?工程师是不是仅仅坐在铺着白纸的桌旁就可以开始设计了呢?当他记下一些设想后,下一步应该做些什么?什么因会影影响或者控制着应该做出的决定?最后,这一设计过程是怎样结束的呢? 有时,虽然并不总是如此,工程师认识到一种需要并且决定对此做一些工作时,设计就开始了。认识到这种需要,并用语言将其清楚地叙述出来,常常是一种高度创造性的工作。因为这种需要可能只是一个模糊的不满,一种不舒服的感觉,或者是感觉到了某些东西是不正确的。 这种需要往往不是很明显的。例如,对食品包装机械进行改进的需要,可能是由于噪音过大、包装重量的变化、包装质量的微小的但是能够察觉得出来的变化等表现出来的。 叙述某种需要和随后要解决的问题之间有着明显的区别。要解决的问题是比较具体的。如果需要干净的空气,要解决的问题可能是降低发电厂烟囱的排尘量,或者是降低汽车排除的有害气体。 确定问题阶段应该制订设计对象所有的要求。这些设计要求包括输入量、输出两特性、设计对象所占据的空间尺寸以及这些参量的所有制约因素。我们可以把设计对象看作是黑箱中的某种东西。在这种情况下,我们必须具体确定黑箱的输入和输出,以及它们的特性和制约因素。这些设计要求将规定生产成本、产量、预期寿命、工作范围、操作温度和可靠性。还存在着许多由于设计人员所处的特定环境或者由于问题本身的性质所产生的隐含设计要求。某个工厂中可利用的制造工艺和设备会对设计人员的工作有所限制,因而成为隐含的设计要求的一部分。例如,一个小工厂中可能没有冷变形加工机械设备。因此,设计人员就必须选择这个工厂中能够进行的其他的金属加工方法。工人的技术水平和市场上的竞争情况也是隐含的设计要求的组成部分。在确定了要解决的问题,并且形成了一系列的书面的和隐含的设计要求之后,设计工作的下一阶段是进行综合以获得最优的结果。因为只有通过对所设计的系统进行分析,才能确定其性能是否满足设计要求。因此,不进行分析和优化就不能进行综合。设计工作是一个反复进行的过程。在这个过程中,我们要经历几个阶段,在对结果进行评价后,再返回到前面的阶段。因此,我们可以先综合系统中的几个零件,对它们进行分析和优化,然后再进行综合,看它们对系统的其他部分有时么影响。分析和优化都要求我们建立或者做出系统的抽象模型,以便对此进行数学分析。我们将这些模型称为数学模型。在建立数学模型时,我们希望能够找到一个可以很好地模拟实际物理系统的数学模型。评价是整个设计过程中的一个重要阶段。评价是对一个成功的设计的最后检验,通常包括样机的实验室实验。在此阶段我们希望弄清楚设计能否真正满足所有的要求。它是否可靠?在与类似的产品的竞争中它能否获胜?制造和使用这种产品是否经济?它是否易于维护和调整?能否从它的销售或使用中获得利润?与其他人就设计方案进行交流和沟通是设计过程的最后和关键阶段。毫无疑问,有许多伟大的设计、发明或创造之所以没有为人类所利用,就是因为创造者不善于或者不愿意向其他人介绍自己的成果。提出方案是一种说服别人的工作。当一个工程师向经营、管理部门或者其主管人员提出自己的新方案时,就是希望向他们说明或者证明自己的方案是比较好的。只有成功地完成这项工作,为得出这个方案所花费的大量时间和精力才不会被浪费掉。人们基本上只有三种表达自己思想的方式,即文字材料、口头表述和绘图。因此,一个优秀的工程师除了掌握技术之外,还应该精通这三种表达方式。如果一个技术能力很强的人在上述三种表达方式中的某一种的能力较差,他就会遇到很大的困难。如果上述三种能力都很差,那将永远没有人知道他是一个多么能干的人!一个有能力的工程师不应该害怕在提出自己的方案时遭到失败的可能性。事实上,偶然的失败肯定会发生的,因为每一个真正有创造性的设想似乎总是有失败或批评伴随着它。从一次失败中可以学到很多东西,只有不怕遭受失败的人们才能取得最大的收获。总之,决定不把方案提交出来,才是真正的失败。机械设计概论机械设计是一门通过设计新产品或者改进产品来满足人类需求的应用技术科学。它是一个广阔的工程技术领域,不仅要研究产品在尺寸、形状和详细结构等方面的基本构思,还要考虑产品在制造、销售和使用等方面的有关问题。进行各种机械设计工作的人员通常被称为设计人员或者设计工程师。机械设计是一项创造性的工作。设计工程师不仅在工作上要有创新性,还必须在机械制图、运动学、工程材料、材料力学和机械制造工艺等方面具有深厚的基础知识。如前面所述,机械设计的目的是生产能够满足人类需求的产品。发明、发现和科学知识本身并不一定能给人类带来益处,只有当它们被用在产品上才能产生效益。因而,应该认识到再一个特定产品进行设计之前,必须先确定人们是否需要这种产品。应当把机械设计看成是设计人员运用创造性的才能进行产品设计、系统分析和制订产品的制造工艺的一个良机。掌握工程基础知识要比熟记一些数据和公式更为重要。仅仅使用数据和公式是不足以再一个好的设计中做出所需的全部决定。另一方面,应该认真精确地进行所有运算。例如,即使将一个小数点的位置放错,也会使正确的设计变成错误的。一个好的设计人员应该勇于提出新的想法,而且愿意承担一定的风险,当新的方法不适用时,就恢复采用原来的方法。因此,设计人员必须要有耐心,因为所花费的时间和努力并不能保证带来成功。一个全新的设计,要求屏弃许多陈旧的,为人们所熟知的方法。由于许多人易于墨守成规,这样做并不是一件容易的事情。以
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